Apparatus and material for core orientation



Dec. 13, 1966 D. E. WINKEL 3,2933% APPARATUS AND MATERIAL FOR COREORIENTATION Filed Dec. 24, 1964 5 Sheets-Sheet 1 INVENTOR.

David 5 Win ke! BY wwm ATTORNEYS Dec. 13, 1966 D. E. WINKEL APPARATUSAND MATERIAL FOR CORE ORIENTATION Filed Dec. 24, 1964 5 Sheets-Sheet 2INVENTOR Do vid E. Win kel ATTORNEYS Dec. 13, 1966 D. E. WINKEL3,291,225

APPARATUS AND MATERIAL FOR CORE ORIENTATION Filed Dec. 24, 1964 5Sheets-Sheet 5 INVENTOR.

David E. Winkel ATTORNEYS Dec. 13, 1966 D. E. WINKEL 3,

APPARATUS AND MATERIAL FOR CORE ORIENTATION Filed Dec. 24, 1964 5Sheets-Sheet 4 INVENTOR.

Dc vid E. Win kel ATTORNEYS Dec. 13, 1966 D. E. WINKEL 3,291,226

APPARATUS AND MATERIAL FOR CORE ORIENTATION Filed Dec. 24, 1964 5Sheets-Sheet 5 MAGNETlC NORTH Fig.22.

, INVENTOR.

David E. Winkel wag ATTORNEYS United States Patent 3,291,226 APPARATUSAND MATERIAL FOR CORE ORIENTATION David E. Winkel, Rte. 1, Box 541,Laramie, Wyo. Filed Dec. 24, 1964, Ser. No. 421,062 15 Claims. (Cl.17544) This invention relates to the determination of the orientation ofcore samples taken from the earths crust and particularly to apparatusand materials for utilizing the earths magnetic field in making suchdetermination. This application is a continuation-in-part of mycopending application Ser. No. 24,924, filed Apr. 27, 1960 for CoreOrientation.

Core drilling is employed in various fields and particularly in themining and petroleum industries in order to secure samples of the earthscrust at predetermined depths to secure subsurface geological data forthe purpose of analysis and study. Full knowledge of the characteristicsof a subsurface formation can be obtained Only if the precise locationand orientation of the core sample before it was taken can bedetermined. Many devices, methods and techniques have been employed forthis purpose. Some are complicated and time-consuming, some are oflimited accuracy, and others have not been entirely satisfactory forvarious reasons.

Some of these methods for core orientation have utilized the earthsmagnetic field in effecting the determination of the position of thecore sample. One such method employs cementitious material in a fluidstate having finely divided particles of ferromagnetic material mixedtherein, the mixture being deposited in a small cavity drilled in thebottom of the bore to be cored. While the mixture is still in a fluidstate, the particles align themselves with the earths magnetic field andare then locked in their position of alignment upon solidification ofthe cementitious material. Thereafter the core is drilled and taken withthe body of solidified mixture remaining in position in the cavity atthe top of the sample and a magnetometer is employed to determine thepolarity of the magnetic particles in the core.

The present invention provides novel material and apparatus constitutingimprovements on the material and apparatus of the type for determiningthe orientation of core samples by employing a fluid mixture ofsolidifiable material and magnetic particles.

It is an object of this invention to provide an improved materialcomprising a mixture of solidifiable liquid and fine magnetizableparticles for location on and adherence to rock and rock-likestructures.

It is another object of this invention to provide an improved device foremplacing a solidifiable magnetic mixture on a well bottom or otherremotely located surface.

It is another object of this invention to provide a device for emplacinga solidifiable mixture on a well bottom or other remotely locatedsurface including an improved arrangement for utilizing the weight ofthe drill assembly for effecting such discharge.

Briefly, in carrying out the objects of this invention in one embodimentthereof a mixture of epoxy resin and finely divided ceramic magneticmaterial together with an agent for effecting solidification at the endof a predetermined period is provided and before use the ceramicparticles are magnetized by subjecting them to a relatively strongmagnetic field. The material is then lowered to the bottom of a well ordrill hole and is discharged so that it spreads over the bottom and thedrilling or emplacing equipment is then removed to take away anymagnetic elements thereof. The magnetic particles in the liquid mixturethen align themselves with the earths 3,291,225 Patented Dec. 13, 1966magnetic field and at the end of the predetermined period the mixturesolidifies, locking the particles in their aligned positions andafiixing the solidified mass securely to the rock. The core sample isthen taken with a drilled-out portion of the solidified mixture adheringtightly thereto.

At the surface the core sample is marked to provide an identifying lineand a small fragment including an identifiable part of the marking isremoved, floated on a liquid in a unidirectional magnetic field, and thedirection of magnetization or polarity of the particles is determined.The core sample is then marked with the direction of the magnetic fieldindicating the direction of the North Magnetic Pole of the earth, thisbeing determined by the known position of the fragment with respect tothe core prior to its removal. One embodiment of the apparatus fordepositing the solidifiable material on a well bottom comprises acharged container in which a mixture of resin and catalyst together withmagnetic particles is prepared immediately before deposit and is thenlowered into the bore. The container is constructed of flexible materialsuch as plastic and a piercing device is provided which pierces thecontainer by impact when the assembly strikes the bore bottom, therebydischarging the material. The assembly is then removed and the materialallowed to harden.

In another embodiment the charged container is provided with twocompartments, one containing the resin and the other the catalyst, andthese are mixed on piercing and discharge, and in a further embodimentthe liquids are contained within a rigid piston structure which strikesthe bottom and actuates the piston to force the liquids outwardly ontothe desired surface.

The features of novelty which characterize the invention are pointed outwith particularity in the appended claims. The invention itself,however, both-as to its organization and method of operation, togetherwith :further objects and advantages thereof may best be understood uponreference to the following description taken in connection with theaccompanying drawings, in which:

FIG. 1 is a sectional view of a well drill assembly at the bottom of thewell in position during emplacement of liquid in accordance with themethod employed with the apparatus of this invention;

FIG. 2 is a view similar to FIG. 1 showing the tool assembly withdrawnfrom position after emplacement of the liquid;

FIG. 3 is an illustration of the same portion of the well with the toolassembly removed and the coring bit in position during the coringoperation;

FIG. 4 is an enlarged view of the liquid charged container employed inthe equipment of FIG. 1;

FIG. 5 is an enlarged sectional view of the lower portion of the chargedcontainer in FIG. 4;

FIG. 6 is a view similar to FIG. 5 showing the container duringdischarge of the liquid;

FIGS. 7, 8 and 9 are views similar to FIGS. 1, 2 and 3, respectively,illustrating coring equipment provided with a liquid charged containerembodying the invention shown during three steps in the method of theinvention;

FIG. 10 is an enlarged view partly in section of the coring bit andcontainer of FIG. 1;

FIG. 11 is an enlarged sectional view of the lower portion of thecontainer;

FIG. 12 is a plan view 'of the bottom of the well bore having thesolidified orientation material of the invention in position thereon andillustrating characteristics of the invention;

FIG. 13 is a view similar to FIG. 12 showing the top of the core afterremoval and illustrating a step in the method of the invention;

FIG. 14 illustrates a magnetic device for determining the orientation ofparticles in accordance with the invention;

FIG. 15 is a view similar to FIG. 13 illustrating the marking of a corein accordance with its determined orientation;

FIG. 16 is a perspective view partly in section of an instrument forfacilitating the determination of the magnetic polarity of particleswith a portion of the instrument removed for purposes of illustration;

FIG. 17 is a perspective view partly in section of the optical systemand azimuth ring for the instrument of FIG. 16;

FIG. 18 is a sectional view along the line 18-18 of FIGS. 16 and 17illustrating the optical system in position on the instrument;

FIG. 19 is a plan view showing the top of the instrument of FIG. 18;

FIG. 20 is an elevation view partly in section of the lower end of acore drill assembly showing a modified form of the liquid chargeapparatus;

FIG. 21 is a sectional elevation view of the charge apparatus takenalong the same central plane as that of FIG. 20; and

FIG. 22 is a chart for use in the method of the invention fordetermining the angular correction required for cores taken fromdeflected bores.

In the drawings the invention has been illustrated in connection withapparatus suitable for placing a charge of solidifiable liquid mixtureincluding a dispersion of magnetic particles at the bottom of the wellbore. The liquid is selected to solidify at the end of a known period oftime and all magnetic materials are removed from the vicinity of thebottom of the well before the end of this time so that the magneticparticles in suspension in the liquid will align themselves only withthe earths magnetic field prior to solidification of the liquid. Aftersolidification, a core sample is taken, the top end of the sample havingthe solidified liquid securely adhering thereto.

Various liquid mixtures may be employed in the apparatus of theinvention and the particular mixtures and solidification times areselected depending upon the depth of the bore hole and the nature of thereservoir formation or rock surface on which the liquid is to besolidified and to which it must adhere securely when solidified.Coloring may 21'1SO be.8.ddd to facilitate recognition of the solidifiedliquid on the core. The solidified liquid must have the characteristicsof adhering securely to the rock or other material to be cored. Variousliquids are suitable for mixture with magnetized particles and may beselected depending upon the requirements of the specific application. Ithas been found that highly satisfactory results may be secured byemploying epoxy resins with a polyamine as the crossinking orsolidifying agent; these resins have the property of wetting rocksurfaces and are admirably suited for securing good attachment of thesolidified material to the core. Furthermore, while various magneticmaterials can be employed and give usable results, it has been foundthat ceramic magnetic materials commonly known as ferrites areespecially useful in the practice of this invention. These ceramicmagnetic materials have a high coercive force so that after beingmagnetized they cannot be demagnetized or remagnetized easily and thusprovide substantially permanent records of their alignment aftersolidification of the liquid. Furthermore, the density of the ceramicmaterials is substantially lower than that of metallic magneticsubstances such, for example, as iron and alnico particles, and as aresult the ceramic materials provide magnetic particles which do notsettle as readily in the liquid and therefore may be kept more uniformlydistributed in the liquid and provide more uniform and reliable results.Furthermore, the ceramic materials are easily powdered and areparticularly suitable to use in a finely divided state which providesthe added advantage of greater sensitivity to alignment.

The nature, size and concentration of the magnetized particles are, asindicated, varied to meet the particular drilling conditions. For someapplications the particles may be of visible size and may besufiiciently large for direct observation; for the purpose of directobservation the particles may be suitably colored or otherwise markedand relatively large particles may be marked by color or shape toindicate their polarity. However, for most of the applications hereincontemplated, the particles will be of small size and direct visualobservation of their orientation is not required.

In order to secure accurate and reliable placement of the liquid mixtureat the bottom of the well to be cored, charged containers are providedwhich include the solidifiable liquid and the magnetizable particlesmixed therein. The container may be charged with a gas under pressure;in another embodiment the liquid is contained in a chamber having apiston therein and is discharged by pressure produced by movement of thepiston upon landing of the drill apparatus. When liquids such as epoxyresins are employed, the solidifying or cross-linking agent such as apolyamine may be isolated within the charged vessel by a frangiblecapsule or diaphragm which may be broken at the time it is to be mixedwith the resin, the solidifying time running from the time of breakingthe capsule or diaphragm. The magnetizable particles may be magnetizedat any time. However, it is preferred for most applications not tomagnetize the particles until they are about to be used, whereupon theycan be magnetized by passing them through a magnetic field. Theconcentration of the magnetic particles may be varied according to therequirements of the particular application. However, for generalpurposes it has been found that a low concentration of magneticparticles provides a very practical type of mixture and avoids atendency to obscure alignment with the earths field which may resultfrom magnetic interaction between the particles when they are inexcessive abundance. For example, a solidifiable substance for the coreorienting method of this invention may comprise an epoxy resin with apolyamine solidifying agent (preferably a higher polyamine) comprisingthe liquid and finely powdered ceramic magnetic material having aconcentration of one-tenth to one gram per liter of the liquid. Withthis mixture, when a solidified fragment is taken from the core it hasbeen found that this fragment may be as small as ten cubic millimetersand still provide an adequate indication of the orientation orpolarization of the mass of particles produced by alignment with theearths magnetic field.

For further purposes of illustration and not by way of limitation,another example of a practical mixture suitable for use in the method ofthis invention comprises an epoxy resin identified as resorcinoldiglycidyl ether with a hardening agent sold by the Dow Chemical Co. asX2654.4. This composition may be employed effectively with ceramicmagnetic materials such as one sold under the trade name Indox-l and thechemical composition of which in BaFe O For storage purposes the chargedcontainers may be kept cool, which increases the viscosity of the liquidand minimizes or prevents agglomeration of the contained particles. Itis particularly desirable to use low temperature storage to keep theviscosity high when the particles have been magnetized before storage.

The solidification time for the liquid mixture may be changedselectively by varying the type or amount of epoxy resin or solidifyingagent to provide periods from a fraction of an hour to many hoursdepending upon the application in which it is to be employed. In thecase of charged containers provided with breakable capsules ordiaphragms each container may be marked to indicate its solidificationperiod, which will depend on the nature of the resin and solidifyingagent employed and the temperature within the particular well bore.

Referring now to the drawings, FIG. 1 illustrates a drill collar 21carrying a drilling bit 22 within a well bore defined by walls indicatedat 23, the bit 22 resting against the bottom of the bore indicated at24. Within the collar 21 there is positioned a standard well survey tool25 including a hollow anchor 26 and a landing shoe 27 secured to thebottom end of the anchor and resting in position against a baffle plate28 at the top of the bit 22. This particular arrangement of the surveytool in the drilling equipment is commonly known as the bottomlandingtype. substance herein described are equally applicable withoutmodification in the survey tool arrangement known as the top-landingtype, where the body of the survey tool passes through the plate and isarrested when an enlarged member of the top of the tool contacts thebaffle plate.

The hollow anchor is provided with a charged container and in FIG. 1 abody of liquid mixture 29 has been shown during its discharge through afluid port 30 in the bit 22. The liquid is discharged through thelanding shoe 27 in a manner to be described below. After the liquid hasbeen deposited as indicated in FIG. 1, the drill assembly is removedfrom the area as indicated in FIG. 2, the distance of removal beingsufficient to prevent any interference with the effect of the earthsmagnetic field on the magnetic particles within the discharged liquid.

In carrying out the method employing the material of the invention asillustrated in FIGS. 1, 2 and 3, the drill assembly is removedcompletely from the well or bore and a coring bit is then employed asillustrated in FIG. 3 to remove a core including a portion of the liquid29 after it has solidified and has attached itself to the bottom of thebore hole 24. As shown in FIG. 3, a coring bit 32 is being operated toremove a core 33 from the bottom of the hole with a portion of the nowsolidified liquid 29 remaining on the top of the core. The coring bit 32is attached to an outer core barrel 34 in the usual way and an innercore barrel 35 is provided in the usual way to receive and retain thecore 33. The material 29 remains securely affixed to the top face of thecore after having been solidified with the magnetic materials dispersedtherein. These materials are aligned by the earths magnetic field andprovide a substantially permanent record for test purposes. After thecore has been brought to the surface it may be positioned in accordancewith the previously secured well data and oriented about its axis by themethod of this invention as more fully described later herein.

The construction and arrangement of the charged container within theanchor section 26 of the standard type well survey tool is clearly shownin FIGS. 4, 5 and 6 where the anchor section is shown containing acharged vessel or pressurized cartridge 36. The cartridge 36 and anchor26 are preferably constructed of a non-magnetic material which may, forexample, be a molded synthetic resin or plastic. Other suitablematerials include aluminum, magnesium, and plastics having glass fibersincorporated in them, all of which may be drilled away should they lodgein the bore. The cartridge is filled to a predetermined level with thesolidifiable liquid 37 and is sealed with a volume of gas under pressureabove the liquid. The cartridge may be fitted with a standard pneumaticvalve 36' through which compressed air or other gas may be admitted tocharge the container to the desired pressure.

Before the cartridge is sealed, a frangible or shatterable capsule,diaphragm or other container 41 filled with suitable solidifying orcross-linking agent for the resin or other liquid 37 is positioned inthe cartridge and attached to the wall of the cartridge well below thesurface of the liquid. This capsule has been shown unbroken in FIG. 4,although in normal use when the cartridge is inserted in the anchorsection the capsule would The devices for emplacing the orienting 6 havebeen broken and the catalyst mixed with the liquid 37 in order to startthe solidification period. The capsule 41 may be broken by a sharp blowagainst the container.

The lower end of the cartridge is provided with an arrangement forbreaking a wall portion of the cartridge and discharging the liquid whenthe tool strikes the bottom of the hole. In cartridges having thefrangible capsule or diaphragm attached to or near the bottom wallportion of the cartridge to be broken, the solidifying agent will bemixed with the solidifiable fluid during the interval of fluiddischarge. The details of construction of the wall piercing and fluiddischarging device are shown in FIGS. 5 and 6. As shown in thesefigures, the landing shoe 27 has a central passage 38 within a tubularfitting 39 which is threaded into the upper portion of the shoe asindicated at 40. The shoe is provided with external threads 42 at itsupper end so that it can be threaded into corresponding internal threadsat the bottom end of the anchor section 26. When the cartridge 36 is tobe placed in the anchor section the shoe 27 is unscrewed and the upperpointed end of the tube 39, indiacted at 43, is pressed into a fitting44 molded as an integral part of the cartridge. The fitting 44 isprovided with a central opening or chamber below a bottom wall portion45 of the cartridge and is provided with intermediate and bottomrestrictions 46 and 47, respectively, which have central openingsslightly smaller than the external diameter of the tube 39. The plasticmaterial of the fitting is sufficiently flexible to be deformed andafford passage for an annular wedge member 48 on the tube 39 which thusenters the lower chamber formed between the restrictions 46 and 47. Thepointed end 43 extends into the upper chamber and lies just below thecartridge wall 45. A second annular wedge 49 is provided on the tube 39in a position to lie outside just below the fitting 44.

The cartridge with the landing shoe and tube 39 assembled in the fitting44 is then inserted in the anchor section 26 and the shoe screwed intoplace at the bottom of the section. The assembly is then dropped orlowered into the drilling tools where it becomes positioned fordischarge as shown in FIG. 1. When the survey tool and anchor 26 strikethe baffie plate 28, the momentum of the cartridge presses the wall 45against the pointed tube which then pierces the wall, the wedge 48entering the upper shoulder of the fitting and the wedge 49 entering thelower, as indicated in FIG. 6. The shape of the annular wedges preventstheir being withdrawn from the cartridge and holds the cartridge andtube in discharging position. The gas under pressure then forces theliquid downwardly through the tube and discharges it onto the surface atthe bottom of the well as indicated by the arrows in FIGS. 1 and 6.Before dropping or lowering the survey tool and combined cartridge intoposition for emplacement of the liquid it may be necessary or desirableto circulate the drilling fluid to clear any chips or debris from thebottom of the bore.

After emplacement of the liquid the tool assembly is raised, as statedheretofore, to remove all magnetic material, and when the equipment hasbeen raised the magnetic particles in the liquid are influenced solelyby the earths magnetic field and align themselves with the field. Whenthe liquid has solidified the particles are locked in their alignedposition and provide a positive indication of the direction of theearths field through the zone at the bottom of the bore, and thus aftercoring provides this indication on the core which indication is notaffected by any turning or twisting of the core during removal.

In the above described embodiment of the invention the liquid emplacingdevice has been employed with a standard surveying tool lowered in theusual manner through the drill stem or collar and it is thus notnecessary to provide a modification of the standard drilling equipment.

The foregoing method using the material of this invention may also bepracticed in connection with standard coring tools by utilizing thepressurized cartridge and without modifying the coring tools for thispurpose. FIGS. 7, 8 and 9 illustrate the same three steps of the methodas FIGS. 1, 2 and 3 but with standard coring tools in all steps. Inthese figures a standard coring tool comprising an outer core barrel 34ahaving a coring bit 32a is employed, an inner core barrel 3511 beingarranged to receive the core in the usual manner. A suitable corecatching and retaining means such as resilient stepped or shoulderedfingers 51 are provided in the usual manner at the lower end of theinner barrel to grip and retain the core.

In this arrangement the charged container or cartridge is constructedsubstantially in the form of a standard core barrel plug or core markerso that it fits the coring tool and may be looked in place until theemplacement of the liquid has been effected. As shown in FIG. 7, apressurized cartridge 52 is positioned and locked in the lower end ofthe coring tool and extends a substantial distance beyond the bit. Thecartridge is provided with a discharge device 53 which is actuated uponstriking the bottom of the bore 24a and deposits the liquid 29a in amanner similar to that of the first embodiment. The impact on strikingthe bottom also breaks the lock and allows the cartridge to move backinto the core barrel 35a as indicated in FIG. 8 showing the coring bitraised after deposit of the liquid 2911. Then when the well is cored asindicated in FIG. 9 the spent cartridge is moved upwardly in the corebarrel in the usual manner of a core marker by the core 33a which isbeing drilled.

The details of construction of the cartridge and discharge mechanism areshown in FIGS. and 11. As shown in FIG. 10 the cartridge comprises ahollow container of plastic such as polyethylene or other easilydrillable and non-magnetic material which is shaped to be adapted to theparticular type of coring tool with which it is employed. In theillustrated arrangement the core catcher 51 is provided with recesseswhich receive integral shearing pins 54 formed on the outer wall of thecontainer 52; these pins lock the container in position and prevent itsdisplacement until the unit strikes the bottom of the bore whereupon thecontained fluid is ejected, as more fully described hereafter, and thepins are sheared off. The cartridge is charged with a solidifiableliquid 55 such as an epoxy resin and a quantity of magnetized ceramicmagnetic particles and charged with gas under pressure, as through apneumatic valve, in the same manner as that of FIG. 4. The cartridge isalso provided with a longitudinal frangible diaphragm 56 separating thesolidifiable fluid 55 from the solidifying agent 55'. For purposes ofcharging, two standard pneumatic valves 52' may be mounted at the top ofthe cartridge one in communication with a respective chamber on eachside of the diaphragm. Thus the liquids are discharged under pressurewhen the device 53 strikes the bottom of the well bore.

As shown in FIG. 11, the device 53 comprises a tube 57 having upper andlower wedge-shaped ends 58 and 59 both of which have perforationsproviding open communication at the two ends of the tube. The upperwedge 58 is flat and is positioned transversely of the diaphragm 56 sothat it will cut into both sides of the diaphragm and release bothliquids. The tube is secured in position by a collar 61 threaded onto aboss or fitting 62 threaded or otherwise secured to the bottom of thecontainer 52. The upper wedge 58 fits in the central opening of thefitting 62 with its point below the wall 65 of the container and withits base resting on the collar 61 which holds it in position. The tubeis also provided with a suitable ridge or key (not shown) to fit acomplementary recess (not shown) at the side of the opening through thecollar and prevent rotation of the tube. A compression spring 63 may bemounted about the tube between the cone 59 and the collar 61 to hold thecone 58 against the collar 61 and minimize the likelihood of accidentalpuncture of the cartridge.

I scribed.

The bottom wall of the container is relatively thin as indicated at 65,and when the device 53 strikes the bottom of the well bore the upperwedge 58 pierces the wall 65 and ruptures the diaphragm 56 and allowsthe liquids 55 and 55 to be discharged by the gas pressure, the liquidsflowing through the tube, mixing therein, and out onto the rock surface.The broad base of the wedge 58 holds the wedge within the containerduring discharge against the pressure in the container which tends toforce the tube outwardly.

The modifications of the invention described above may be employed withstandard types of equipment as de- In some applications it may bedesirable to drop or otherwise deposit a charged container or cartridgeinto the well after the drilling equipment has been removed and then tolower the coring tools, break the cartridge in position at the bottomthereby releasing the liquid, then withdrawing the tools as before and,after solidification of the liquid, drilling the cores, the cartridgecasing being of drillable material and being drilled away in the coringprocess. The cartridges for this method of operation may, for example,be one of the cartridges 52 of FIG. 7 with the ejection device 53removed as it is not required when the cartridge is to be broken by thedrill. Other forms or shapes and sizes of the charged cartridges may beemployed and, for example, may be relatively small spherical cartridgesa plurality of which are dropped into the well or admitted with thedrilling fluid. Such capsules may also be constructed with sufficientweight added that they will sink through the circulating medium ordrilling fluid and settle to the bottom rapidly after the circulationhas stopped. These containers which are to be broken by the drillingequipment need not be pressurized. However, pressure ejection andtheforced discharging of the liquid will help in many cases to effectbetter emplacement of the liquid on the surface of the rock to be cored.Also when employing the plurality of small cartridges, some may containthe resin and ceramic magnetic powder while others contain thesolidifying agent, the mixing being effected upon breaking of thecartridges at the bottom of the well.

After the core sample has been taken with the solidified liquid affixedto its end, it is necessary to determine the direction or polarity ofthe aligned particles. Fig. 12 illustrates the bottom of a well bore 24awith the solidified magnetic-particle mixture 29a covering a portion ofthe bottom. For purposes of illustration the earths magnetic field atthe bottom of the bore hole has been indicated by a plurality ofparallel arrows 66 pointing in the same direction toward Magnetic Northand the particles have been shown as short lines 67 in the material allparallel to the magnetic field or arrows. As mentioned heretofore, theparticles may be visible and may even be colored or otherwise marked toindicate their north pointing poles; however, for most applications themagnetic particles will be in minute or powder form. The short straightlines of FIG. 12 nevertheless serve to illustrate the action with eithertype of particle.

The alignment of the particles may be determined by testing a very smallfragment of the solidified plastic as already mentioned. In FIG. 13,which is a plan view of the central portion of the same rock formationas FIG. 12 after being cut and removed as a core, the core has beenshown after the solidified mixture has been marked and is ready for theremoval of a circular fragment 68. The core has been marked by drawing astraight line 69 across the top of the solidified plastic and a secondshort parallel line 70 close to it. The fragment 68 is cut so that theline 70 extends only a short distance across it to serve as a positionindicator. This short line thus identifies the position of the fragmenton the core and facilitates correct placing of the fragment when it isreturned to the core after determination of its polarity. The fragmentis preferably cut or otherwise removed so that it is taken from a planesubstantially at right angles to the axis of the core.

After the fragment has been cut from the body of material it is testedin a simple magnetic device a basic form of which is shown in FIG. 14.The device provides a body of liquid 72 in a non-magnetic cup or vessel73 which rests between north-attracting and south-attracting pole pieces74 and 75, respectively, of a U-shaped magnet 76. The fragment 68 isfloated on the liquid and remains substantially at the middle of thevessel due to surface tension forces of the liquid. The fragment is freeto rotate and aligns itself with the relatively strong magnetic field ofthe magnet, the north-seeking pole of the fragment, as determined by thealignment of the contained magnetized particles, pointing toward thenorthattracting pole of the magnet as represented by the arrow 77indicated on the water surface. The angle between the straight lines onthe fragment and the direction of the field is then measured as byobserving a protractor (not shown) placed across the rim of the cup 73.For purposes of illustration the fragment 68 is shown in FIG. 15replaced to its original position on the core and the magnetic northline 77 marked at the measured angle with respect to the line 69. Inactual practice, however, only the angular difference between the lines69 and 77 as described need be transferred to the core; the fragmentneed not be replaced. Any suitable system of marks or method of markingmay beemployed, the parallel lines being shown as one suitable andsimple method by way of example.

An instrument for facilitating the more precise determination of thedirection of alignment or polarity of the particles is shown in FIGS. 16through 19. The instrument comprises a rectangular box having a base 79of non-magnetic material on which are supported northattracting andsouth-attracting magnetic pole pieces 80 and 81, respectively, and areturn magnetic path comprising the four side walls 82, 83, 84 and 85 ofthe case. The poles 89 and 81 are spaced apart and a-vessel or vial 37is mounted centrally in the space between the poles, a circular recess86 being provided in the base 79 to receive the vessel. The case iscompleted by a nonmagnetic cover on top 88 having a circular centralopening 89 which receives the upper end of the vessel 87. A ring 91 isfixed to the top 88 concentric with the opening 89 and acts as a seat orretainer for an optical system shown in FIG. 17.

The optical system comprises a vertical tube 92 having a flange 93 whichfits on the ring 91 as shown in FIG. 18. The tube and flange have beenshown as molded from a single piece of transparent material, the lowerface of the flange being stepped or rabbeted to fit over the ring 91. A360 azimuth ring or plate 94 is secured by a small screw 94 to theflange 93 at the stepped portion so that the azimuth ring may be readthrough the transparent plastic. A north index line or member 95 issecured to the top of the case at the center line of thenorth-attracting magnet so that it may register with the marking on theazimuth ring. The optical system is thus mounted so that it may berotated about a vertical axis coinciding with the central vertical axisof the vessel 87.

The optical system includes a reticle 96 comprising a transparent discmarked with a plurality of spaced lines 97 parallel to the 180 axis ofthe aximuth ring as shown in FIG. 19. A magnifying lens 98 is providedfor viewing the reticle when aligning the lines 97 with marks on objectssuch as a floating fragment indicated at 68a which is similar to thefragment 68 of FIGS. 13 to 15. The lens 98 is held on the tube 92 by athreaded collar 100 and the reticle 96 is secured to the lower end ofthe tube 92 by a threaded collar or retainer 101.

The liquid in the vessel 87 is selected to provide the required buoyancyof the objects to be floated, and in the case of plastic fragments maybe water. The body of liquid fills the vessel to a level fairly close tothe position of the reticle to facilitate the registering of the reticlelines with identifying marks such as the line 69a on the fragment 68a.In the illustrated position of FIG. 19 the reference line 69a of themagnetized fragment is at 45 to the center line of the magnetic poles8t] and 81; thus, during solidification of the liquid, the earthsmagnetic field is indicated to have passed through the core from whichthe fragment 65a was taken at an angle of 45 to the reference linemarked on the core. The true line representing the direction of theearths magnetic field on the core in its original position in theformation may now be marked on the core by drawing a line 45 to theoriginal reference line 69a, essentially the same as the north arrow '77of FIG. 15, the direction of the 45 polarity line being determined withrespect to the fragments original position on the core.

The azimuth ring 94 includes a concentric slot 102 to receive theattachment screw 94', which slot permits adjustments in the position ofthe azimuth ring to allow for minor corrections of alignment with thereticle lines and to compensate for the local declination of the earthsmagnetic field if desired. Such declination adjustments are usual insurvey tools and allow for direct determination of true north ratherthan magnetic north; however, such adjustments can be used only withcores taken from essentially vertical well bores.

This instrument provides a simple, rugged and accurate device fordetermining the polarity or magnetic field direction of small fragmentsof solid material.

FIGS. 20 and 21 illustrate an embodiment of the apparatus of thisinvention wherein the liquid resin and solidifying agent are maintainedseparately and not under pressure until the apparatus reaches the bottomof the drill hole. Upon reaching the bottom, both liquids are dischargedunder pressure by a piston device and are mixed and placed on the bottomwall of the drill hole. In FIGS. 20 and 21 this embodiment of theinvention is illustrated as secured in a conventional core drillingassembly like that of FIGS. 3 and 10, and corresponding parts of thedrill assembly have been designated by the same numerals with the sufiixletter b.

The liquid emplacing device indicated at 105, and which is of generallycylindrical configuration and provided with a plunger 1116 at the bottomend thereof, is mounted in engagement with the shouldered fingers 51b ofthe core catching and retaining means at the lower end of the corebarrel 35b. Displacement of the apparatus 195 is prevented by two shearpins 197 positioned diametrically of each other and engaging therecesses in opposite ones of the fingers 51!). As shown in FIG. 21, thepins 167 are threaded into the cylindrical body 195.

The plunger 106 comprises a cylindrical piston body having a concentricreduced portion 108 at its upper end. The main body is slidably mountedin a cylindrical chamher 110 formed within the block 195 and the reducedsection 108 enters and is slidably mounted in a piston chamber 111 ofcorrespondingly reduced cross section. The plunger 196 is secured withinthe block 105 on oppositely positioned shear pins 112 having their outerends threaded into threaded passageways in the walls of the body 105.The shear pins 112 are weaker than the pins 107 and are sheared onimpact when the assembly bottoms on the drill hole and the plunger 106strikes the bottom wall. Thus the piston 196 moves upwardly in the block105 which remains latched in position at the end of the core barrel 35b.In order to charge the chambers formed by the pistons 106 and 1118,screw plugs 113 and 114, respectively, are unscrewed and the liquidinjected into the chambers while the plunger 106 is secured in positionby the pins 112.

The resin with fine magnetic particles dispersed therein is injectedinto the chamber 111 and the solidifying agent into the chamber 111). Apassage 115 connects the chamher 111 with a recess 116 in the end of theplunger 106 and inclined passages 117 connect the chamber 110 with thepassage 115.

It will be apparent that when the piston 106 moves upwardly in the block105 liquid is forced out of the chambers 110 and 111 and dischargedthrough the passages 115 and 117. The liquids are thus mixed anddischarged together into the recess 116 and thus onto the bottom of thedrill hole. The drill assembly is then moved away from the bottom of thebore and the material with its magnetic particles allowed to solidify toretain the particles in their positions of alignment with the earthsmagnetic field.

The chambers 110 and 111 are charged with liquid, but some air is leftin them and forms top air spaces indicated at 118 and 119, respectively.The air in the chambers is compressed upon actuation of the pistons andnot only reduces the shock on impact but results in a discharge of airthrough the passages 115 and 117 after the liquid has been dischargedand thereby facilitates the cleaning of the passages for recharging.

After the material has solidified, the drill assembly is again loweredto the bore bottom. The lowering provides suflicient weight to shear thepins 107, and as drilling proceeds the apparatus 105 enters the corebarrel and thus is retrieved with the core. If desired, this shearingaction may be effected before withdrawal of the assembly to allowsolidification of the liquid. In this case, the cylinder 105 may beprovided with a shoulder to assure its being caught above the shoulderson the core fingers 51b after shearing of the pins 107 so that thedevice does not drop into the bore hole when the assembly is withdrawnfor solidification of the liquid.

In order to prevent mixing of the resin and solidifying agent before theapparatus reaches the bottom of the bore, a temporary stopper ofsuitable material may be released at the inlets of the passages, thestopper being driven out through the passages under the piston pressure;however, for most purposes the small size of the passages together withthe sealing of the chambers 110 and 111 will prevent leakage of theliquid. Furthermore, the solidification time may be selected to be suchthat the liquids will not solidify even should they mix in the passagesduring the relatively short period after filling of the chambers andbefore the drill assembly reaches the bottom of the bore.

In the foregoing description of the methods and apparatus fordetermining the orientation of cores taken from the earths crust, it hasbeen assumed that the core was taken from a substantially vertical wellbore. In practice the bore or well may lie at very substantial angles ofdeflection from the vertical. Because the earths magnetic field may alsobe inclined below the horizontal by widely different angles depending onthe location on the earths surface, it becomes necessary whenever thedeflection of a bore hole exceeds say 5 from the vertical to introduce acorrection in the determination of core orientation by the method ofthis invention.

It is common practice in surveying bore holes to determine the amount ofdeflection from the vertical and the direction of such deflection. Thisinformation is thus available from the standard well surveys. The amountof correction required for deflected bores may be determined as an anglewith respect to the horizontal at which the orientation polarity line,determined as fully described heretofore, marked across the flat end ofa core must be set to effect correct orientation of the core. Thecorrection factor can be computed for any magnetic dip and any angle anddirection of the bore hole deflection for use with the orientationmethod of this inevntion by means of the following formula:

(sin 1) (tan D) tan C(cos I) (tan SH- where C=desired correction anglein degrees, I=defiection in degrees of bore hole from vertical neardepth of cored rock,

D=dip in degrees of earths magnetic field below horizontal at locationof well, S=magnetic direction of bore hole deflection, established 0 ateast and West at north, and +90 at south FIG. 22 is a chart prepared byusing the above equation and indicates the correction factors for alocation where the earths magnetic dip or inclination is 70. The charthas been drawn in four quadrants, east of north, west of north, east ofsouth and west of south, respectively. The radial lines thus representthe magnetic compass direction of the deflection of the well .bore. Theamount of deflection of the bore is indicated in degrees by concentriccircles and on this chart bore deflections up to 30 are indicated, asdesignated along the horizontal axis of the chart. The correctionfactors in degrees as calculated by the formula are indicated by thecurved lines. In utilizing these correction factors, the core ispositioned according to the data obtained from the well survey and,where the bottom of the bore is deflected in the western two quadrants,the core and the north end of the polarity line are rotated clockwisebelow the horizontal by the amount of the positive correction factor andcounter-clockwise above the horizontal by the amount of the negativecorrection factor. Conversely, where the bottom of the bore hole isdeflected in the eastern two quadrants, the core and north end of thepolarity line are rotated counter-clockwise below the horizontal forpositive correction factors and clockwise above the horizontal fornegative correction factors. This positions the north end of thepolarity line at the proper rotational position according to thedirection of the bore hole deflection with respect to the verticalnorth-south magnetic plane. The zero correction or horizontal positionof the polarity line on the core is represented by a curved line markedzero in the central part of the upper two quadrants of FIG. 22. Allcorrection factors within these Zero arcs are negative and those outsidepositive.

By way of illustration, a line has been drawn on FIG. 22 representing abore deflected north 62 east. The deflection of the bore as determinedfrom well survey data is assumed to be 18, the line thus terminating atthe 18 circle. This point is about halfway between the +20 and +30correction curves so that a correction factor of +25 will be necessaryto correct for the deflected bore hole. The orientation polarity line,for example 77 of FIG. 15, is determined as described in detailheretofore and the core is positioned in the attitude of the bore holeas determined from the usual well survey. Since the bore hole isdeflected in an eastern quadrant and the correction factor is positive,the core is then rotated counterclockwise about its axis so that thenorth end of the polarity line is directed 25 below the horizontal, thuscompletely orienting the core in the position it occupied at the bottomof the deflected bore hole used as an example.

The somewhat egg-shaped zone about the intersection of the 0 northradial line and 20 deflection circle is an area of substantialcoincidence of the inclination or dip of the earths magnetic field andthe bore hole deflection so that the lines of the earths field runsubstantially along the core and no reliable indication of direction ororientation of the core may be secured in this zone. When survey dataindicate that the well bore is within this zone, it is, of course,necessary to determine the orientation of the core by other methods thanrelying on the earths magnetic field.

From the foregoing it is readily apparent that the material of thisinvention together with the apparatus thereof makes possible a simple,quick and reliable method for determining core orientation whichrequires minimum interruption of the operation of the standard drillingor coring procedures or equipment. This method greatly shortens the timefor determining core orientation and is readily adaptable to use in thefield.

While the invention has been described in connection with specific formsof the method employed therewith and embodiments of the material andapparatus, various modifications and other applications will occur tothose skilled in the art. Therefore it is not desired that the inventionbe limited to the specific methods and constructions illustrated anddescribed and it is intended by the appended claims to cover allmodifications which fall within the spirit and scope of the invention.

I claim:

1. A material for use in the determination of the direction of Weakmagnetic fields which comprises a liquid having the property ofsolidifying at the end of a pre determined time and a mass of finelydivided magnetizable ceramic particles mixed in said liquid, saidparticles being substantially permanently magnetized upon subjection toa relatively strong magnetic field whereby after magnetization of saidparticles and when said liquid and mixed ceramic particles are subjectedto a weak magnetic field the particles will align themselves with thefield and upon solidification of the liquid will be retained in suchalignment.

2. A material for use in the determination of the direction of weakmagnetic fields which comprises a liquid polymerizing resin and a massof finely divided magnetizable ceramic particles therein and a settingagent, said particles being substantially permanently magnetized uponsubjection to a relatively strong magnetic field whereby upon agitationof said material and the addition of the setting agent said particleswill align themselves 'with whatever magnetic field they are subject toand upon setting of the resin will be retained in such alignment.

3. A material for use in the determination of the direction of weakmagnetic fields as set forth in claim 2 wherein said ceramic particlesare in powdered form and are of a low concentration in said liquidresin.

4. A material for use in the determination of the direction of weakmagnetic fields as set forth in claim 2 wherein said setting agent is ahigher polyamine.

5. A material for use in the determination of the direction of weakmagnetic fields as set forth in claim 2 wherein said resin is an epoxyresin.

6. A material for use in the determination of the direction of weakmagnetic fields as set forth in claim 5 wherein said ceramic material isin finely powdered form and is of a concentration of one-tenth to onegram per liter of said epoxy resin.

7. In the art of determining the orientation of a remote object withrespect to a weak magnetic field and employing the orientation ofmagnetic particles with respect to such field, a fluid-charged devicecomprising a closed container of non-magnetic material and a body ofsolidifiable liquid in said container, said liquid having the propertyof solidifying at the end of a predetermined period, a mass of finelydivided particles of magnetizable ceramic material in said liquid, andmeans for discharging the mixture whereby the solidification of themixture may take place outside of the container.

8. In the art of determining the orientation of remote objects, afluid-charged device as set forth in claim 7 wherein said container ischarged under pressure and includes a rupturable portion and saiddis-charge means includes a release element positioned to pierce saidportion and release the pressurized charge when said element is pressedagainst said portion of said container.

9. In the art of deter-mining the orientation of remote objects, afluid-charged device as set forth in claim 8 wherein said container isof a size and shape to fit within and constitute a portion of a welltool assembly and said element is positioned and arranged to releasesaid charge upon bottoming of the tool assembly.

MB. In the art of determining the orientation of a remote object withrespect to a weak magnetic field and employing the orientation ofmagnetic particles with respect to such field, a fluid-charged devicecomprising a closed container of non-magnetic material and a body ofsolidifiable liquid resin in said container, a mass of finely dividedparticles of magnetizable ceramic material in said liquid resin, meansfor maintaining a charge of solidifying agent in said container out ofcontact with said resin, means for releasing said solidifying agent andmixing said resin and said agent, and means for discharging the mixturewhereby setting of the mixture may take place outside the container.

11. In the art of determining the orientation of remote objects, a fluidcharged device as set forth in claim 10 wherein said container hasflexible walls and said solidifying agent maintaining means includes afrangible member within said first mentioned container which may bebroken by force applied to the walls of said first container to releasethe solidifying agent into the liquid resin.

12. A liquid discharge device arranged to be mounted in a core drillassembly or the like for the emplacement of solidifiable material on thebottom of a drill hole or the like comprising a body having a cylinderchamber therein and a piston slidably mounted in said chamber, said bodybeing movable through the core barrel of a core drill, a first frangiblemeans for securing said body in a core drill assembly, a secondfrangible means for securing said piston in spaced relation to the endof said cylinder chamber for providing a space for the storage of aliquid to be discharged, a foot member connected with said piston andextending below said body and beyond a core drill assembly when saidbody is mounted therein, said device including passage meanscommunicating with said chamber and the lower portion of said device fordirecting liquid discharged from said chamber downwardly onto a surfacecontacted by said foot member, said first frangible means being weakerthan said second frangible means whereby upon engagement of said memberwith a surface the downward force of the drill assembly first releasessaid piston to discharge the liquid and releases said body from saiddrill assembly upon application of increased force whereby said body ismoved upwardly upon coring and may be removed with the core.

13. A liquid discharge device for mounting in a drill assembly or thelike for the emplacement of solidifiable materials on the bottoms ofdrill holes and the like comprising a body having a plurality ofchambers for holding charges of liquid therein, liquid discharge meansincluding pistons in said chambers, a surface engaging foot extendingbeyond said body for urging said pistons into said chambers when thedrill assembly bottoms on a drill hole or other surface, means lockingsaid pistons in fixed spaced relationship to the ends of said chambers,said locking means being disengaged for releasing said pistons from saidbody upon application of a predetermined force urging said pistons intosaid chambers, and means for securing said body in a drill assembly withsaid foot extending beyond the assembly whereby force may be applied tosaid locking means when said portion strikes a drill hole bottom or thelike and said locking means thereby released, said device having fluidpassage means communicating with said chambers for directing fluiddischarged from said chambers onto a surface contacted by said foot whenthe weight of the assembly rests thereon.

14-. A liquid discharge device as set forth in claim 13 wherein saidfluid passage means comprises a discharge passage extending through saidpiston and opening adjacent said foot and branch passages connectingrespective ones of said chambers with said discharge passage whereby thefluids from said chambers are mixed in said discharge passage and themixture is discharged adjacent said foot onto the surface struckthereby.

15. A liquid discharge device for mounting in a drill assembly or thelike for the emplacement of solidifiable materials on the bottoms ofdrill holes and the like comprising a rigid body having a cylindricalopening therein,

said opening having a cylindrical extension of smaller diameterconcentric therewith, a piston s-lidably mounted in said cylinder andhaving a reduced concentric cylindrical portion for sliding movement insaid cylinder extension, frangible means for retaining said piston in aposition spaced from the end of said cylinder and said extension andproviding first and second chambers respectively for accommodatingseparate charges of liquid, means in said piston providing communicationwith said chambers and including a common discharge passage for mixing10 whereby said piston may be struck to break said frangible means andto move into said chambers and discharge liquid through said commonpassage.

References Cited by the Examiner UNITED STATES PATENTS 2,140,097 12/1938 Vacquier 175--44 X 2,292,838 8/1942 Jones l7544 2,964,793 12/1960Blume 252-625 CHARLES E. OCONNEL, Primary Examiner.

R. E. FAVREAU, Assistant Examiner.

1. A MATERIAL FOR USE IN THE DETERMINATION OF THE DIRECTION OF WEAKMAGNETIC FIELDS WHICH COMPRISES A LIQUID HAVING THE PROPERTY OFSOLIDIFYING AT THE ENDS OF A PREDETERMINED TIME AND A MASS OF FINELYDIVIDED MAGNETIZABLE CERAMIC PARTICLES MIXED IN SAID LIQUID, SAIDPARTICLES BEING SUBSTANTIALLY PERMANENTLY MAGNETIZED UPON SUBJECTION TOA RELATIVELY STRONG MAGNETIC FIELD WHEREBY AFTER MAGNETIZATION OF SAIDPARTICLES AND WHEN SAID LIQUID AND MIXED CERAMIC PARTICLES ARE SUBJECTEDTO A WEAK MAGNETIC FIELD THE PARTICLES WILL ALIGN THEMSELVES WITH THEFIELD AND UPON SOLIDIFICATION OF THE LIQUID WILL BE RETAINED IN SUCHALIGNMENT.